Chill cast iron alloy



Patented Jan. 22, 1935 CHILL CAST IRON ALLOY Paul D. Merica, New York, N. Y., and James 8. Yanick, Elizabeth, and Thomas H. Wickenden, Roselle, N. J., assignol's to The International Nickel Company, Inc., New York, N. 1., a corporation of Delaware No Drawing. Original application October 21, 1926, S6118] No. 143,293. Divided and all! llplication June 6, 1934, Serial No. 729,236

20 Claims.

This invention relates to alloys and more especially to chill cast nickel bearing iron alloys. The invention relates particularly to castings formed by casting nickel bearing iron compositions against chills to form castings having exranges:

Per cent Carbon 2-4 Silicon .25-2 Manganese .25-2 Nickel 2-10 Chromium Up to 4 Phosphorus and sulphur may be present within the ranges usually found in cast iron, as for instance phosphorus .03 to 1.15% and sulphur .03 to See any edition of Kent's handbook, 1900 and later; Moldenke, Principles of Iron Founding, edition of 1917, page 198, Hatfield, Cast Iron In the Light of Recent Research; and others. In respect to the ranges of phosphorus and sulphur in chilled, white and gray iron castings such as for rolls, cams, brake shoes, gears, plow points, etc., phosphorus ranges from, under .10 to 1.0% and sulphur .04 to 25%. See particularly pages 196, 182, 183, 199 and 198 in their order of Moldenkes Principles of Iron Founding, 1917, where both the phosphorus and sulphur for chilled rolls must be, under .3 and 09% respectively, and for chilled castings in general. As indicated on page 183, the phosphorus and a sulphur shall be, below .20 and .06% respectively.

On page 199, it is shown Again, the sulphur and wherein sulphur is recited from .05 to .20% and it states in the lower part of that page'and in respect to the above sulphur content-In this composition phosphorus is supposed to be well below 10%;"

Itisalsotobenotedthatthe ranges of analyses of American, as well as for-- and consistent 'type of pig iron must be used.

Such ranges are to be found in Appendix II of Hatflelds Cast Iron in the Light of Recent Research, second edition 1918 and third edition 1928.

The composition may bevaried somewhat, if desired, by the addition of other alloying materials, such as molybdenum, tungsten, titanium, copper, etc. The carbon content is within the general range usual for cast iron, from either air furnace or cupola.

Casting compositions lying within those ranges are particularly desirable in that good adjustment of nickel, chromium, silicon and carbon contents is secured to nicely regulate the depth of chili.

We find that the amount of chill in the chill cast iron may be maintained sensibly constant ii nickel and chromium are added as alloying materials inabout theratioof 2 or3 to1,sayabout 2 to 1. We also find that the amount of chill may be nicely controlled by suitably adjusting the various elements according to the rough rule that 1 part carbon equals 3 silicon, 1 part silicon equals 2 parts nickel, 1 part chromium equals 2 parts nickel, and 1 part sulphur equals '10 parts silicon; increasing the silicon, carbon and nickel acts to decrease the chill, whereas, increasing the chromium and sulphur acts to increase the chill. The silicon and carbon contents may be lowered, if desired, by using a higher ratio of nickel to chromium than that mentioned above, the increased chilling tendency accompanying the lowered silicon and carbon contents being counteracted by the higher nickel content. It is to be noted that the foregoing is to be taken into consideration in connection with the statement and expression used herein that the nickel is present in the'proportion of 2 or 3 to l of chromium.

For ordinary work, however, we have obtained good results with a composition containing about the following percentages:

Per cent Carbon 8.0 Manganese 6 Silicon 1. 0 Nickel 4. 5 Chromi m Phosphorus and sulphur may be present within therangesusuallyfoundincastiron,asindicated above. a

Such a composition, if chill cast, will give a white iron having a Brinell hardness of 550, as compared with the 400-500 of ordinary chilled iron. The chilled metal under tension has a transverse strength of 8000 pounds for 1% inch square bars tested on 12 inch centers in comparison with'about 0000 poundsfor ordinary high carbon chilled iron. Gray iron having this composition has a tensile strength of about 35,000 pounds per square inch. in comparison with 20,000 to 25,000 psi for high carbon iron ordinarily used for chill work.

Our composition has the further advantage that it is subject to heat treatment and. the hardnessandtoughnessmaybesomodinedifdesired.

The composition is not only extremely hard in the chilled condition, but it is strong and tough both in the chilled condition and in the ray condition. These characteristics render the composition desirable forchilled castingsto be sub- :lected to heavy pressure or impact. since such castings are less liable to breakage than ordinary chilled iron castings.

We are aware that nickel has been proposed as an addition material to reduce the chilling effect in iron alloys, and that chromium has been proposed as a hardener. We have found, however, that a proper proportion should be maintained betweenthe nickel and chromium with reg changed from the softer pearlite'of ordinary chilled iron castings into the harder martensite or troostite. Martensii'e is often associated with austenite and; hence by martensite, we mean martensite or austenite or both in association. Hence the resulting hardness is between that of the very hard iron carbide grains and the martensite having a Brinell hardness of from 550 up to about'l50 where the carbon is about 3.50%. This hardness may be regulated somewhat by proportions of the alloy or the use of equivalents.

A further important advantage ofour invention resides in the provision of an improved chill casting alloy wherein the depth of chili may be nicely controlled by suitable adjustment of the addition elements. Cast iron of our composition may be made either in the air furnace or cupola, and we intend to cover such composition of cast iron made in either type of furnace.

The present application is a divisional case of our co-pending application, Serial No.'143,203, filed October 21, 1920.

We claim:

1. A chilled iron casting containing about 2 to about 4% of carbon, about 0.25% to about 2% of silicon, about 2% to about 8% of nickel, about 0.25% to about 2% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, and less than about 1.5% of manganese,

the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensi e and grains of metallic carbide and practically free from graphite.

2. Achilledironcastingcontainingabout 2 to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, and less than about 1.5% of manganese, the said iron being constituted of a structure comprising a surface of exceedingly tough .white iron'having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite.

. 3. A chilled iron casting containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion'of 2-3 to one of chromium, and about 0.15% to about 1.5% of manganese, said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practicallyfree from graphite with a strong, tough gray iron of martensitic character adjacent thereto.

4. A chilled iron casting containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4% ofchromium, the nickel being present in the proportion of 2-3 to one of chromium, less than about 1.5% of manganese and sulphur not over about 0.25%, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and coinposed mainly of martensite and grains of metallic carbide and practically 'free' from graphite with astrong, tough gray iron of martensitic character adjacent thereto.

' 5. A chilled iron casting containing about 2% to about 4% of carbon, about 0.25% to about. 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, less than about 1.5% of manganese, and phosphorus not over about 0.40%, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron havinga hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite with a strong, tough gray iron of martensitic character adjacent thereto.

6. A chilled iron casting containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, less than about 1.5% of manganese, sulphur not over about 0.25%. and phosphorus not over about 0.40%, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite with a strong, tough gray iron of martensitic character adjacent thereto.

7. A chilled iron casting containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, less than about 1.5% of manganese, and a small but effective amount of molybdenum, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite.

8. A chilled iron casting containing about 2% to about 3.75% of carbon, about 0.25% to 1.25%

. of silicon, about 2.5%,to about 5% of nickel, about 0.5% to about 3.0% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, and about'0.15%-to about 1.25% of manga'nese, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite. v

9. A chilled iron casting containing about 2% to about 4% of carbon, about 2% to about 5% of nickel, and a small but effective amount of silicon, chromium, and manganese, the nickel being present in the proportion of 2-3 to one of chromium and the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite with a strong, tough gray iron of martensitic character adjacent,

thereto.

10. A chilled iron casting containing about 2% to about 4% of carbon, about 2% to about 5% of nickel, and a small but effective amount of silicon, chromium, molybdenum, and manganese, the nickel being present in the proportion of 2-3 to one of chromium and the said-iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite with a strong, tough gray iron of martensitic character adjacent thereto.

11. An iron roll containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2% to about 8% of nickel, about 0.25% to about 2% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, and about 0.15% to about 1.5% of manganese, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from ra e 12. An iron roll containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4%. of chromium, the nickel being present in the proportion of 2-3 to one of chromium, andless than about 1.5% of manganese, the said iron being constituted of a structure comprising a surface -of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite.

13. An iron roll containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, and

14. An iron roll containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, less than about 1.5% of manganese, and sulphur not over about 0.25%, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite with a strong, tough gray iron of martensitic character adjacent thereto.

15. An iron roll containing about 2% to'about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, less than about 1.5% of manganese, and phosphorus not over about 0.40%, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite with a strong, tough gray iron of martensitic character adjacent thereto.

16. An iron roll containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about-5% of nickel, about 0.25% to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, less than about 1.5% of manganese, sulphur not over about 0.25%, and phosphorus not over about 0.40%, the said iron being constituted of a structure comprising a surface ofexceedingly tough white iron having a hardness of about 550 Brinell and. higher and composed mainly of martensite and grains of metallic carbide and practically free from graphite with a strong, tough gray iron of martensitic character adjacent thereto.

17. An iron roll containing about 2% to about 4% of carbon, about 0.25% to about 2% of silicon, about 2.0% to about 5% of nickel, about 0.25%

' to about 4% of chromium, the nickel being present in the proportion of 2-3 to one of chromium,

less than about 1.5% .of manganese, and a smallbut effective amount of molybdenum, the said iron being constituted of a structure comprising a surface of exceedingly'tough white iron having a hardness of about 550 Brinell and higher and composed mainly of-martensite and grains of metallic carbide and practically free from graphite with a strong, tough gray iron of martensitic character adjacent thereto.

18. An iron roll containing about 2.0%-to about 3.75% of carbon, about 0.25% to 1.20% of silicon, about 2.5% to about 5% of nickel, about'0.5% to about 3.0% of chromium, the nickel being present in the proportion of 2-3 to one of chromium, and about 0.15% to about 1.25% of manganese, the said iron being constituted of a structure comprising a surface of exceedingly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains of metallic carbide and practically free from graphitewithastrong,tough-grayironoimartensitic character adjacent thereto.

19. Anircnrollcontainingaboutfl; toabout 4% of carbonhabout 2% to about 6% of nickel,

and a small but eiiective amount of silicon, chromium and manganese, the nickel being present inthepmportionotmtooneoichromiumand the said iron being constituted of a structure com- 5 20.Animnroilcontainingabout2%toabout 4% of carbon, about 2% to about 5% otnickel, and a small but eitective amount 01 silicon, chromium, molybdenum and manganese, the nickel being present in the proportion of 2-3 to one of chromium and the said iron being constituted of a structure comprising a surface 0! exceedinginaly tough white iron having a hardness of about 550 Brinell and higher and composed mainly of martensite and grains 0! metallic carbide and practically tree from graphite with a strong, tough gray iron oi marteneitic character adjacent thereto. PAUL D. MERICA.

JAMES B. VANICK.

THOMAS H. WICKENDEN. 15 

